Multilayer filter

Abstract

A multilayer filter wherein the capacitances of capacitors are reduced to reduce the size of the filter without substantially affecting the filter frequency characteristics. A predetermined filter circuit includes plural electrodes in a dielectric ceramic device body. Each of the capacitors is respectively disposed at input and output ends of the filter circuit and has one end connected to one of input/output terminals. Winding-type inductors, interposed between the input/output terminals and the one ends of the capacitors, are in the device body.

1 . A multilayer filter comprising filter circuit including a plurality of electrodes in a dielectric device body, first and second capacitors respectively disposed at input and output ends of the filter circuit, each of the capacitors having one end connected to one of two input/output terminals of the filter circuit, and inductors in the device body interposed between the input/output terminals and the one ends of the capacitors. 
   
   
       2 . The multilayer filter according to  claim 1 , wherein the inductors include a winding. 
   
   
       3 . The multilayer filter according to  claim 1 , wherein each of the inductors includes first and second ends and further comprising:
 two or more further capacitors connected in series between the first ends of the inductors having the one ends respectively connected to the input/output terminals, and   a series circuit including an inductor and a capacitor connected between a ground point and a connection point between the further capacitors and one of the first and second capacitors.   
   
   
       4 . The multilayer filter according to  claim 3 , wherein the two or more further capacitors connected in series between the other ends of the two inductors have the one ends respectively connected to the input/output terminals are stacked in a first region,
 the first inductor connected to one of the input/output terminals is in a second region adjacent to the first region,   the second inductor connected to the other of the input/output terminals is in a third region existing in such a position that the third region and the second region being symmetrical with respect to the first region, the first region being located between the third region and the second region, and   the series circuit of the inductor and the capacitor connected between the ground point and the connection point between the further capacitors connected in series between the other ends of the inductors is in a fourth region adjacent to the first to third regions.   
   
   
       5 . An electronic component comprising a module including mounting an IC mounted on the multilayer filter  claim 1 . 
   
   
       6 . An electronic component comprising a module including an IC mounted on the multilayer filter of  claim 2 . 
   
   
       7 . An electronic component comprising a module including an IC mounted on the multilayer filter of  claim 3 . 
   
   
       8 . An electronic component comprising a module including an IC mounted on the multilayer filter of  claim 4 . 
   
   
       9 . A multilayer band pass filter comprising:
 a dielectric block carrying stacked layers including first, second, third, fourth, fifth, sixth and seventh layers, the dielectric block being interposed between each pair of the layers, each of the layers including planar electrically conducting elements,   the first, second and seventh layers including grounded planar electrically conducting elements electrically connected to each other by via conductors,   first and second terminals of the filter, the first and second terminals including planar electrical conducting elements respectively at first and second opposite ends of the stacked layers,   a first series inductor including winding segments in the fourth, fifth and sixth layers, the winding segments of the first series inductor including planar electrically conducting elements that are connected to each other by via conductors that are in the fourth, fifth and sixth layers, the winding segment in the fourth layer being connected by a via conductor to the first terminal,   a first series capacitor including the planar electrically conducting element in the sixth layer that is included in the first inductor and a planar electrically conducting element in the fifth layer,   a second series capacitor including the planar electrically conducting element in the fifth layer that is included in the first capacitor and a planar electrically conducting element in the third layer,   circuit elements connecting the planar electrically conducting element of the second series capacitor in the third layer to the second terminal,   a first shunt inductor including winding segments in the third, fourth, fifth and sixth layers, the winding segments of the first shunt inductor including planar electrically conducting elements that are connected to each other by via conductors and are in the third, fourth, fifth and sixth layers, the winding segment of the first shunt inductor in the sixth layer being connected by a via connector to the planar electrically conducting element of the first and second series capacitors in the fifth layer, and   a first shunt capacitor including the planar electrically conducting element of the first shunt inductor in third layer and the grounded planar electrically conducting element in the second layer.   
   
   
       10 . The filter of  claim 9  wherein the circuit elements connecting the planar electrically conducting element of the second series capacitor in the third layer to the planar electrically conducting element of the second terminal includes a third series capacitor, a second series inductor, a second shunt inductor and a second shunt capacitor,
 the third series capacitor including the planar electrically conducting element of the second series capacitor in the third layer and an ungrounded planar electrically conducting element in the second layer,   the second shunt inductor including planar electrically conducting elements that are connected to each other by via conductors and are in the fourth, fifth and sixth layers, the planar electrical conductors of the first series inductor and the second shunt inductor in the fourth, fifth, and sixth layers differing from each other, the planar electrical conductor of the second shunt inductor in the third layer being included in the second shunt capacitor,   the second shunt capacitor further including the ground electrical conductor in the second layer,   the second series inductor including winding segments in the second, third and fourth layers, the winding segments of the second series inductor including planar electrically conducting elements that are connected to each other by via conductors and are in the third, fourth and fifth layers, the winding segment of the second series inductor in the fifth layer being connected by a via conductor to the first terminal.   
   
   
       11 . The filter of  claim 10  wherein the planar electrical conducting elements of the second and sixth layers include superfine and rectangular portions, the superfine portions in the second and sixth layers being respectively winding portions of the second and first series inductors, the rectangular winding portions in the second and sixth layers being respectively electrodes of the first and third series capacitors. 
   
   
       12 . The filter of  claim 11  wherein the positions of the rectangular and serpentine portions in the second and sixth layers are reversed from each other. 
   
   
       13 . The filter of  claim 12  wherein the serpentine portions include two substantially parallel legs;
 the legs in the second layer being aligned with legs of the second series inductor in the third layer, one of the legs in each of second and third layers being aligned with a leg of the second series inductor in the fourth layer;   the legs in the sixth layer being aligned with legs of the first series inductor in the fifth layer, one of the legs in each of the fifth and sixth layers being aligned with a leg of the first inductor in the fourth layer.